Screening of phytotoxicity of Alternaria macrospora MKP1 against Parthenium hysterophorus L.

Parthenium hysterophorus L. an exotic, pernicious weed is considered as one of the most troublesome weeds for agricultural sector by virtue of its high ecological amplitude and adaptability. Microbes and their by-products are now proved to be a worthy alternative to toxic chemicals used for weed management. Alternaria macrospora MKPI was isolated from the parthenium leaves infected with leaf blight and found pathogenic to the weed. The herbicidal potential of cell free culture filtrate of A. macrospora MKP1 has been tested against parthenium by employing detached leaf bioassay and seed germination bioassay and a significant damage was exhibited by the cultural filtrate of pathogen to the parthenium leaves and seeds.     

Pseudomonas putida NBRIC19 provides protection to neighboring plant diversity from invasive weed Parthenium hysterophorus L. by altering soil microbial community

Parthenium hysterophorus L. (Parthenium) is an invasive weed species which is spreading worldwide affecting natural ecological systems, biodiversity, crop production and human health. The present study was conducted to evaluate the potential of plant growth promoting Pseudomonas putida NBRIC19 in detoxifying the phytotoxic effect of Parthenium. Significant increase in C/N ratio, macronutrients, and micronutrients was observed in P. putida NBRIC19-treated soil. P. putida NBRIC19 treatment of the soil provided protection to plant communities in Parthenium invaded area, as the species diversity had increased in the treatment as compared to non-bacterized soil. P. putida NBRIC19 treatment besides Parthenium, also succeeded in controlling other weed species like Commelina benghalensis and Cynodon dactylon. In addition to this, the impact of Parthenium was also studied on functional microbial diversity based on carbon source utilization pattern. It was observed that P. putida NBRIC19 treatment of soil had shifted the microflora in such a manner that utilization of toxic allelochemicals increased to lessen their phytotoxic effect. Taken together, these results suggest that soil treatment with P. putida NBRIC19 may be used as a promising biological control measure for controlling the phytotoxic effect of Parthenium and in protecting ecosystem integrity of neighboring plants in Parthenium invaded areas.     

Herbicidal activity of volatile oils from Eucalyptus citriodora against Parthenium hysterophorus

The herbicidal effect of volatile oils from leaves of Eucalyptus citriodora against the noxious weed Parthenium hysterophorus was tested. In a laboratory bioassay, seed germination and seedling length, chlorophyll content and respiratory activity of Parthenium decreased with increased concentration of eucalypt oils from 0.2 to 5.0 nL mL^‐1. Germination was completely inhibited at 5.0 nL mL^‐1 eucalyptus oils. Further, for 4‐week‐old plants of Parthenium sprayed with different concentrations of volatile oils, visible damage increased and chlorophyll content and respiratory activity decreased with increased concentration from 0 to 100 μL mL^‐1, the week after spraying. At concentrations up to 50 μL mL^‐1, plants showed some recovery over time but plants sprayed with 75 and 100 μL mL^‐1 died 2 weeks after treatment. Plants sprayed with 50 μL mL^‐1 and higher concentrations of eucalypt oils were desiccated and wilted in appearance. At concentrations of 5–75 μL mL^‐1, eucalypt oils caused a rapid electrolyte leakage from the Parthenium plants thereby indicating an effect on membrane integrity. It is concluded that volatile oils from E. citriodora possess weed‐suppressing ability and could be used as a potential bioherbicide for future weed management programmes.     

Aerobiology and some chemical parameters of Parthenium hysterophorus pollen

Parthenium hysterophorus, a recently invaded toxic weed, in Eastern India, is now growing gregariously in Salt Lake City — a newly developed township situated in the eastern fringe of the metropolitan city of Calcutta. The floristic survey revealed that most of the trees and shrubs in Salt Lake City have been introduced except for a few, which were recorded as natural occurrence, Parthenium being most prevalent among them. Ecological associations of Parthenium in various localities of Salt Lake City were also investigated. Aerobiological survey was done using a Burkard seven day Volumetric Spore Trap, with the object to record the occurrence of Parthenium pollen in the air of Salt Lake in different seasons along with other airborne types. A total of 45 pollen and 60 fungal spore types were trapped and recorded. The frequency of grass and cyperaceous pollen were found to be dominant followed by Trema. Frequency of Parthenium was relatively insignificant. Chemical analyses of the pollen grains of Parthenium including assay of carbohydrate, lipid, protein, etc., were done. Clinically one out of six patients showed ELISA positive reaction to Parthenium pollen.     

Characterization of a toxin fromParthenium hysterophorus and its mode of excretion in animals

Fractionation of methanolic extracts of air dried aerial parts ofParthenium resulted in the isolation of a toxic constituent which was identified as parthenin, the major sesquiterpene lactone from the weed. The LD₅₀ (minimal lethal dose required to cause 50% mortality) for parthenin in rats was 42 mg/kg body weight. When [³H]-parthenin was given orally or by intravenous administration, radioactivity appeared in the milk of lactating laboratory and dairy animals. Tissue distribution of radioactivity revealed that maximum label was detectable in kidneys.     

Evaluation of Alternaria alternata ITCC4896 for use as mycoherbicide to control Parthenium hysterophorus

Mycoherbicides are specialty biotechnology products which employ the use of fungi or fungal metabolites as non-chemical alternatives, thereby reducing the input of harmful chemicals to control noxious weeds. The present communication emphasises the potential of an indigenous isolate of Alternaria alternata ITCC 4896 as a mycoherbicide for the global weed Parthenium hysterophorus. Of the various spore concentrations tested by in vitro detached leaf bioassay, 1 × 10⁶ spores/ml was the most effective, inducing 89.2% leaf area damage on the seventh day and was further tested by the whole plant bioassay. Both in vitro detached leaf assay and whole plant bioassay exhibited a similar trend in disease development, exhibiting 50% damage at 96 hours post-treatment. However, 100% mortality was observed in the whole plant bioassay on the seventh day. This is the very first report on the bioweedicidal potential of Alternaria alternata ITCC 4896 (LC#508) for use as a mycoherbicide for Parthenium hysterophorus.     

Interaction between arbuscular mycorrhizal fungus Glomus mosseae and plant growth promoting fungus Phoma sp. on their root colonization and growth promotion of cucumber (Cucumis sativus L.)

Interaction between arbuscular mycorrhizal fungus Glomus mosseae and plant growth promoting fungus Phoma sp. was studied for its effect on their root colonization and plant growth of cucumber. Two isolates of Phoma sp. (GS8-2 and GS8-3) were tested with G. mosseae. The percent root length colonized by G. mosseae was not adversely affected by the presence of Phoma isolates. In contrast, the root colonization of both isolates GS8-2 and GS8-3 in 4-week-old plants was significantly reduced (80.7% and 84.3%, respectively) by added G. mosseae. Inoculating plants with each Phoma isolate significantly increased the shoot dry weight. However, dual inoculation of each Phoma isolate with G. mosseae had no significant effect on growth enhancement.     

Zum Auftreten von Phoma nigrificans (P. Karst.) comb. nov. (Teleomorph Didymella macropodii Petrak) an Winterraps (Brassica napus L. var. oleifera Metzger)

On the occurrence of Phoma nigrificans (P. Karst.) comb. nov. (teleomorph Didymella macropodii Petrak) on winterrape (Brassica napus L. var. oleifera Metzger) With a screening for resistence of winterrape to Phoma lingam (teleomorph Leptosphaeria maculans), in various places in North Germany, another species of Phoma was repeatedly isolated from plants with blackleg symptoms. This Phoma species could easily be distinguished from P. lingam by its larger conidia and its lower optimal temperature. Comparative study with isolates in the Phoma-collection of the “Plantenziektenkundige Dienst” (Wageningen) showed that it, represents the anamorph of Didymella macropodii, an Eurasian Ascomycete occurring on different wild crucifers and originally described from Macropodium nivale in Siberia. The Phoma-anamorph of this fungus was first described in Finl, and from Armoracia rusticana as Sphaeronaema nigrificans. This binomial is now transferred to Phoma (“section Sclerophomella”). Inoculation of rape seedlings with Phoma nigrificans (Didymella macropodii) resulted, in dark discolorations and constrictions of the hypocotyls of the seedlings.     

Biocides formulation of essential oils having antimicrobial activity

Essential oils of fennel, peppermint, caraway, eucalyptus, geranium and lemon were tested for their antimicrobial activities against some plant pathogenic micro-organisms (Fusarium oxysporum, Alternaria alternate, Penicilium italicum Penicilium digitatum and Botyritus cinerea). Essential oils of fennel, peppermint, caraway were selected as an active ingredient for the formulation of biocides due to their efficiency in controlling the tested micro-organisms. Successful emulsifiable concentrates (biocides) were prepared from these oils using different emulsifiers (Emulgator B.L.M. Tween20 and Tween80) and different fixed oils (sesame, olive, cotton and soybean oils). Physico-chemical properties of the formulated biocide (spontaneous emulsification, emulsion stability test, cold stability and heat stability tests as well as viscosity, surface tension and pH) were measured. The prepared biocides were ready to be tested for application in a future work as a safe pesticide against different pathogens.     

Assessment of the effect of biosurfactant produced by Pseudomonas aeruginosa in lethality of Bacillus thuringiensis Berl. against 3rd instars larvae of white cabbage butterfly (Pieris brassicae L.)

Surfactant that is produced from cheap sources like oil sludge by biological agents such as bacteria can be used in various industrial processes. For example, it can be used in environmental processes such as bioremediation and elimination of environmental pollutants, and acts as synergistic agents and distributor pesticides on waxy leaves in agriculture. In this study, biosurfactant which is produced by Pseudomonas aeruginosa (isolated from petroleum sludge) at the intervals of 24, 48, 72 and 96?h, along with chemical surfactant Tween 80 and the biological control agent, Bacillus thuringiensis, in a pilot project for controlling one important cabbage pest (Pieris brassicae), their synergistic properties were evaluated. Statistical analysis of the results showed that B. thuringiensis in combination with biosurfactant produced at different times and B. thuringiensis in combination with chemical surfactant Tween 80 when compared with control treatments like B. thuringiensis alone and B. thuringiensis plus tween 80 as positive controls and distilled water as negative control have significant differences (p?<?0.05). This research showed that surfactant treatment produced at the intervals of 24 and 48?h in combination with B. thuringiensis has the greatest synergistic effect when compared to chemical surfactant treatment. This study concluded that biosurfactant can be used as a distributor and synergistic agent against plant pests and in addition to this, their biological roles in bioremediation can be used as a viable alternative to non-economical chemical surfactants that annually enter millions of tonnes of harmful chemical substances into the fields and underground water.     

Effect of tween series surfactants on alkaloid production by submerged cultures of Claviceps species

Supplementation of Tween surfactants promoted alkaloid production by submerged cultured of Claviceps sp. strain SD-58. Tween 80 (0.5%) exhibited the maximum (2-fold) stimulatory effect when added to the medium at the initial stage of cultivation. The stimulation of alkaloid production by Tween 80 was found to be associated with the increase in cell mass, higher consumption of nutrients and enhanced excretion of alkaloids from the cells. The results are discussed in relation to the physiology of alkaloid production in Claviceps sp. strain SD-58.     

Marine-derived Phoma—the gold mine of bioactive compounds

The genus Phoma contains several species ubiquitously present in soil, water, and environment. There are two major groups of Phoma, viz., terrestrial and marine. After 1981 researchers all over the world have focused on marine-derived Phoma for their bioactive compounds. The marine Phoma are very rich sources for novel bioactive secondary metabolites, which could potentially be used as drugs. Recently, a large number of structurally unique metabolites with potential biological and pharmacological activities have been isolated from the marine Phoma species particularly Phoma herbarum, P. sorghina, and P. tropica. These metabolites mainly include diterpenes, enolides, lactones, quinine, phthalate, and anthraquinone. Most of these compounds possess antimicrobial, anticancer, radical scavenging, and cytotoxic properties. The present review has been focused on the general background of Phoma, current approaches used for its identification and their limitations, difference between terrestrial and marine Phoma species. In addition, this review summarizes the novel bioactive compounds derived from marine Phoma and their biological activities.

     

Interspecific variation in persistence of buried weed seeds follows trade‐offs among physiological,chemical, and physical seed defenses

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Comparative efficiency of different pretreatment methods on enzymatic digestibility of Parthenium sp.

The potential of Parthenium sp. as a feedstock for enzymatic saccharification was investigated by using chemical and biological pretreatment methods. Mainly chemical pretreatments (acid and alkali) were compared with biological pretreatment with lignolytic fungi Marasmiellus palmivorus PK-27. Structural and chemical changes as well as crystallinity of cellulose were examined through scanning electron microscopy, fourier transform infra red and X-ray diffraction analysis, respectively after pretreatment. Total reducing sugar released during enzymatic saccharification of pretreated substrates was also evaluated. Among the pretreatment methods, alkali (1 % NaOH) treated substrate showed high recovery of acid perceptible polymerised lignin (7.53 ± 0.5 mg/g) and significantly higher amount of reducing sugar (513.1 ± 41.0 mg/gds) compared to uninoculated Parthenium (163.4 ± 21.2) after 48 h of hydrolysis. This is the first report of lignolytic enzyme production from M. palmivorus, prevalent in oil palm plantations in Malaysia and its application in biological delignification of Parthenium sp. Alkali (1 % NaOH) treatment proves to be the suitable method of pretreatment for lignin recovery and enhanced yield of reducing sugar which may be used for bioethanol production from Parthenium sp.     

Effects of growth conditions on the lipid composition of Bifidobacterium bifidum subsp. pennsylvanicum

Lipid-phosphorus and lipid-galactose content and phospholipid and fatty acid composition of Bifidobacterium bifidum subsp. pennsylvanicum were examined under a wide variety of growth conditions. Cells from 29-C cultures contained less lipid-phosphorus than did cells from 37-C cultures, but their lipid-galactose content and phospholipid composition did not differ. At both temperatures, the growth phase influenced the lipid composition similarly.Phosphate, Mg²⁺ and K⁺ concentrations in the medium did neither significantly change the cellular lipid-phosphorus content nor the phospholipid composition. Only Mg²⁺-deficiency markedly reduced growth and lowered the content of cellular lipid-galactose.Omission of Tween 80 from the medium did not affect growth, but lowered the content of lipid-galactose and augmented those of lipid-phosphorus and diphosphatidylglycerol in the cell. Increased osmolarity and substitution of other Tweens for Tween 80 caused the same changes in lipid composition, and besides inhibited growth. Omitting Tween 80 and replacing it by other Tweens dramatically reduced the percentage of unsaturated fatty acids. C₁₂- and C₁₄-fatty acids made up about 50% of total fatty acids in cells from Tween 20 cultures and 12–14% in cells from Tween 40 and Tween 60 cultures. The differences in the decline of unsaturated fatty acids and in the degree of replacement of these acids by C₁₂- and C₁₄-fatty acids may be related to the variations in growth in cultures with various Tweens by way of changes in the physical state of the membrane lipids.The present investigations have been carried out with financial support from the Netherlands Organization for the Advancement of Pure Research (ZWO) through the Netherlands Foundation for Chemical Research (SON).     

Medium optimization of a hydrophilic solvent‐stable protease from Serratia sp. SYBC H

Two statistical methods were used for medium optimization for a hydrophilic solvent‐stable protease production by Serratia sp. SYBC H with duckweed as the nitrogen source. Orthogonal design was applied to find the significant variables, then response surface methodology (RSM), including Box–Behnken central composite experiments, was used to determine the optimal concentrations and interaction of the significant variables. Results demonstrated that duckweed powder, wheat flour, Tween 80, sodium chloride had significant effects on the solvent‐stable protease production. The interaction between duckweed and wheat flour was significant. The optimal level of the variables for the maximum protease production was duckweed 43.9 g/L, wheat flour 20 g/L, sodium chloride 0.08 M, Tween 80 1% v/v, initial pH 11.0, and inoculum size 7% v/v. The maximum protease activity reached 1922.8 U/mL in the optimized medium, with about 18.3‐fold higher than that in the unoptimized medium. Most importantly, the protease from Serratia sp. SYBC H has successfully catalyzed the specific acylation of sucrose in a two‐solvent medium consisting of pyridine and n‐hexane (1:1, v/v), and non‐specific acylation of sucrose in anhydrous DMSO. These results demonstrated that the protease from Serratia sp. SYBC H is a solvent‐stable protease and it could be an ideal biocatalyst for sugar esters syntheses in non‐aqueous media.     

Studies on Pathogenic Leptospirae

Effect of Tween 80 on the growth of Leptospira canicola strain Utrecht and L. icterohaemorrhagiae strain Mikawajima was examined. The suspension of washed leptospira was inoculated into modified Korthof's basal medium containing varied amounts of Tween 80 and cultured at 30 C. Cell numbers were counted by using Petroff-Hausser counting chamber every other day. Optimum Tween 80 concentrations for L. canicola were 0.0125 and 0.025%. Cell counts in the second sub-cultures reached 10⁸ per ml the same as the primary cultures. Generation time of L. canicola in 0.025% Tween 80 medium was about 13 hours. Growth of L. icterohaemorrhagiae was inhibited at concentrations greater than 0.0125 per cent. Cell numbers increased about 4 times at concentration of 0.0000125% Tween 80. L. canicola utilizes Tween 80 as a nutrient while L. icterohaemorrhagiae appears sensitive to it. A difference of more than 1,000 times in maximal growth-supporting concentration between L. canicola and L. icterohaemorrhagiae exists. This difference appears to be caused by difference in surface structure and metabolic requirements.     

Factors influencing β-glucosidase production, activity and stability inNectria catalinensis

The influence of different cultivation conditions on β-glucosidase production and of some parameters on the activity and stability of this enzyme were studied inNectria catalinensis. Maximal β-glucosidase production was achieved with ammonium nitrate (0.5 g N/L) as nitrogen source. Tween 80, Tween 20 and Triton X-100 increased β-glucosidase yields, Tween 80 was the most effective for enzyme release and growth at a concentration of 3.4 mmol/L. On the other hand, Tween 20 and Triton X-100 had an inhibitory effect onN. catalinensis growth. A temperature of 23°C and an initial pH of cultures of 6.5 were optimal for biomass and β-glucosidase production. Under optimal cultural conditions (ammonium nitrate, 0.5 g N/L; Tween 80, 3.4 mmol/L; 23°C; initial pH 6.5) the β-glucosidase yield was increased more than five fold respect to the initial state. Optimal temperature for β-glucosidase activity was 45°C, the initial activity dropped 60 % after 6 h of incubation at this temperature. Optimal pH for enzyme activity was 5.3. At this pH the β-glucosidase was completely stable after 3 d of incubation. TheV andK _m values calculated from Lineweaver-Burk and Eadie-Hofstee plots were 0.23 μmol 4-nitrophenol per min per mg of protein and 0.25 mmol 4-nitrophenol β-d-glucopyranoside per L, respectively. The activation energy according to Arrhenius plot was 49.6 KJ/mol.     

Identification of Newly Isolated Talaromyces pinophilus and Statistical Optimization of β-Glucosidase Production Under Solid-State Fermentation

Fungi able to degrade agriculture wastes were isolated from different soil samples, rice straw, and compost; these isolates were screened for their ability to produce β-glucosidase. The most active fungal isolate was identified as Talaromyces pinophilus strain EMOO 13-3. The Plackett–Burman design is used for identifying the significant variables that influence β-glucosidase production under solid-state fermentation. Fifteen variables were examined for their significances on the production of β-glucosidase in 20 experimental runs. Among the variables screened, moisture content, Tween 80, and (NH₄)₂SO₄ had significant effects on β-glucosidase production with confidence levels above 90% (p < 0.1). The optimal levels of these variables were further optimized using Box–Behnken statical design. As a result, the maximal β-glucosidase activity is 3648.519 U g^?1, which is achieved at the following fermentation conditions: substrate amount 0.5 (g/250 mL flask), NaNO₃ 0.5 (%), KH₂PO₄ 0.3 (%), KCl 0.02 (%), MgSO₄ · 7H₂O 0.01 (%), CaCl₂ 0.01 (%), yeast extract 0.07 (%), FeSO₄ · 7H₂O 0.0002 (%), Tween 80 0.02 (%), (NH₄)₂SO₄ 0.3 (%), pH 6.5, temperature 25°C, moisture content 1 (mL/g dry substrate), inoculum size 0.5 (mL/g dry substrate), and incubation period 5 days.